I followed some techniques with my last scrapper auto and now I want to ask your views on some for a final decision

1) When trolling for goods around town , is it better to keep in a low gear so trans shifts less. Doing this of course limits your speed to a safe RPM.

2) If you hit a spot that needs time to load what is you max time you let it idle .2 min 5 min 20 min. pros to letting it run less starter wear and possibly
the motor to stay at peek temp for best combustion.
I have heard some people say motors burn good amt of fuel at start up.

have any tips